Work support for press brake

ABSTRACT

Disclosed is an attachment for a metal forming machine, such as a press brake, in which a stationary bed carries the lower part of a die which is approached by a ram carrying the upper part of the die, or punch. It includes a member secured to the forming machine ram which engages a pivotally supported arm as the punch engages the work to be formed. The arm extends under the work adjacent the forming die and pivotally moves to lift and support the work as forming continues.

United States Paten Morguson [76] Inventor: George G. Morguson, R. R. 2, New Assistant Rogers Paris, Ohio 45347 Attorney, Agent, or FirmWoodard,' Weikart, Emhardt & Naughton [22] Filed: Nov. 21, 1973 21 A LN 417 897 l 1 pp 0 [57 ABSTRACT 52 U.S. c1. 72/386 72/421 Discksed is an attachment 3 metal forming 51 Int. Cl 1121a 9/14 chine-151mb as a Press k which a Stationary bed 5 Field f Search 72/380, 383 385, 386, carries the lower part of a die which is approached by 72/389, 269/55, 56 a ram carrying the upper part of the die, or punch. It includes a member secured to the forming machine 5 References Cited ram which engages a pivotally supported arm as the UNITED STATES PATENTS punch engages the work to be formed. The arm extends under the work adjacent the forming die and 3,390,566 7/1968 Conklm 72/386 pivotany moves to ft and Support the work us form ing continues.

7 Claims, 6 Drawing Figures t {A i h I l l WORK SUPPORT FOR PRESS BRAKE Primary Examiner-C. W, Lanham WORK SUPPORT FOR PRESS BRAKE BACKGROUND OF THE INVENTION In the forming of bends in sheet metal by cold working the metal in a press brake, it often is necessary to have one or more operators lift and support the sheet material which extends from the portion of the sheet actually interposed between the bending die elements. To properly form the sometimes quite lengthy, rectilinear bends in the work, skill is required of the operators to support or lift the stock, that is, the free, extending portion of the sheet, to the desirable degree as the mating dies form the proper bend configuration in the adjacent portion of the sheet. A means for automatically providing the correct lifting and supporting function, eliminating the skilled gaging of the lift required by an operator, has obvious advantage in metal forming operations. Attempts to provide such means are not unknown in the prior art; U.S. Pat. Nos. 2,368,478, 3,715,907 and 3,748,890 disclose typical prior art structures.

The attachment of the present invention performs the function described above by providing a member which is attached to the press ram and moves with the punch to pivotally move a support arm underlying the stock. The arrangement is simple and trouble-free.

Since the attachment member is moved with the ram, the stock lifting action cannot get out of synchronization with the forming die stroke. Adjusting means are provided for adapting the attachment to a relatively wide range of sheet material gauge or thickness.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary, enlarged, side view of the typical press brake showing the moveable and stationary die portions with a portion of the sheet material to be formed interposed between the die members.

FIG. 2 is a fragmentary front view of the press brake structure shown in FIG. 1 with the attachment of the present invention attached to the structure.

FIG. 3 is a side view of the attachment of the present invention.

FIG. 4 is a top plan view of the lower, or stationary portion of the apparatus shown in FIG. 3.

FIG. 5 is a side view of the attachment shown in FIG. 3 but illustrating the positions assumed by the attachment components when the press brake die members are closed, the view shown being generally taken along the line 5-5 of FIG. 2.

FIG. 6 is a view similar to FIG. 5 but illustrating the attachment adjusted to perform its proper function when a lighter gauge stock is being processed by the press brake.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring initially to FIG. 1, there is fragmentarily indicated at 10 the vertically moveable ram portion of a conventional press brake. The press ram supports the primary punch, or moveable portion of the die, indicated at 11. As here shown, the punch exhibits a 90 angle between its inclined faces 11a and 11b. It will be understood that, depending upon the bend or other type of forming operation being carried through, differently angled dies, for example, might also be utilized.

Supported on the stationary bed 12 of the press brake is a die block or portion 13 providing a cavity 14 formed by the inclined faces 13a and 13b, the cavity accommodating the similarly shaped portion of the punch 11. A portion of the sheet material stock is shown at 16 interposed between die members 11 and 13, and it will be understood that, in the conventional operation of the press brake, the punch 11 will press the interposed stock 16 into the cavity 14 with the punch bottoming the stock against the inclined cavity faces. As such forming proceeds, the extending, free portion of'thc sheet material will be required to swing upwardly into a position indicated generally by broken lines 16a in FIG. 1.

During this movement of the extending portion of the stock from its solid line position to its broken line position of FIG. 1, as the punch forms the material, it is important that this extending portion of the stock be properly lifting and supported. The attachment of the present invention, to be described with reference to FIGS. 2-6 accomplises this function.

The attachment includes a holder 21 whose upwardly extending portion 21a is clamped in the conventional press ram 10. As may best be seen in FIG. 2 the clamp portion of the press ram 10 extends sidewardly beyond the conventional punch 11, the holder 21 being aligned with the punch 11 in the ram. The holder 21 carries an actuator member 22 which is adjustably clamped, by screws 23 to the holder 21. The screws 23 extend through elongated slots in the holder 21 and thus permit limited vertical adjustability of the actuator 22 with relation to the holder 21 and the ram 10. The auxiliary punch or actuator formed by the members 21 and 22 moves vertically with the ram 10 and in unison with the punch 11. The actuator 22 has a tapered lower end and its tip engages the flat, horizontal top surface 24 of a pivoted bar or arm 26.

The pivot pin 27, which forms the pivotal axis for the bar 26 is carried by, and extends sidewardly from a parallelogram shaped block 28. The bar is provided with an anti-friction bushing receiving the pin. The slide block 28 is adjustably positionable in a groove or track 29 formed in the upper component or portion 31 of an auxiliary die or stationary member which is completed by the auxiliary die base component 32 having a downwardly extending tab 33 which is clamped, in convention fashion, to the press bed 12. The auxiliary stationary die, formed by members 31 and 32, is horizontally aligned with the stationary die portion 13 which is utilized, in cooperation with the die punch l l, to form the sheet material or stock. The auxiliary punch or actuator, in contrast, has the function, not of forming the stock, but of engaging and moving arm 26. The upper component 31 of the auxiliary, stationary die is rigidly attached to the base portion 32 by means of four shimmed screws 36. The shims 36a, encircling the screws 36, may be moved, one-by-one as desired, to a position between the members 31 and 32, one such position of the shims being shown in FIG. 6. The adjustability of the member 31 with respect to the base 32 by means of the shims 36a enables the attachment to be adapted to various thickness of stock being processed by the press brake as will subsequently be described.

A threaded aperture is jointly formed in the auxiliary die component 31 and in the side margin of the slide block 28 and receives an adjusting screw 37. As may be seen in FIG. 4 the adjusting screw 37 is accessible at the upper surface of the die component 31 and adjustment of the screw 37 serves to raise or lower the sliding block 28 within the track 29, thus adjusting the vertical position of the bar 26 and its actuatorengaged surface 24.

As may best be seen in FIGS. 3 and 4 the block 31, is provided with a 90 V-shaped slot having inclined side surfaces 41a and 41b, the slot extending rectilinearly from the plane surface 24 of the bar 26. The V- shaped groove accommodates the inclined side surfaces of the actuator 22 when the press is closed, that is, when the ram of the press, and the components attached to it, are in their lower position with respect to the bed 12 of the press. As will be evident from FIG. 3, downward movement of the actuator 22 engages the surface 24 of the arm 26, pivoting it clockwise as viewed in FIG. 3, and continued downward movement of the actuator 22 eventually causes it to bottom against the surfaces 41a and 41b.

Referring to FIG. 4, the arm 26 may be seen to extend sidewardly and carries, by means of countersunk screws 42, a board 43 providing a flat surface which, as may be seen in FIG. 2, underlies the portion of the stock extending freely from that portion 16 which is interposed between the primary punch 11 and the stationary die component 13 and which is formed as the press closes. Again referring to FIG. 2, it will be understood that while one of the attachments is there shown positioned at one die of the primary punch and stationary die component, a duplicate attachment might be attached to the press ram and bed at the opposite side of the apparatus so that, assuming a relatively wide sheet of material is to be formed in the press brake, both sides of the stock 16 would be supported by boards 43. Where the stock to be formed is not overly wide, only one of the attachments, as illustrated, need be used.

As may best be seen in FIGS. 3 and 4, the base portion of the auxiliary die identified at 32 has a sidewardly extending portion 32a which carries a threaded member 51. The member 51 houses a compression spring (not shown) which urges outwardly, to the limit of its travel, an abutment pin 52 which engages the underside of the arm 26, the member 51 thus providing a spring loaded abutment which can be used, by adjusting its position, to level the arm 26 and to provide a cushion for the counterclockwise, or return, motion of the arm. The arm 26 and the board 43 carried thereby may be provided with magnetic hold-downs, additional cushioning devices or tie strips extending between the boards 43 where two of the attachments are used, all of these additional components being optional and used where required. As may best be seen in FIG. 5, the stationary portion 31 is provided with a side cover 56, the cover 56 being held in place by the screws 57 which are also visible in FIG. 2. The cover 56 carries ball plungers 58 which bear against the side surface of the block 28 and a bronze disc 59 (FIG. 5) acts as an antifriction surface for the end of the pin 27.

In operation, referring particularly to FIG; 2, the stroke of the ram and the placement of the primary punch 11 and stationary member 13 are adjusted so that the portion of the sheet material interposed between these elements, identified at 16 in FIG. 1, is driven by the punch 11 into the V-shaped cavity 14 (FIG. 1) and the lower edge of apex of the primary punch 11 bottoms against the stock driven into the cavity as the press is closed. As may be seen in FIG. 2, the

sheet material or stock 16 (having a given thickness or gauge such as, for example, 12 gauge) is interposed between the punch and the stationary portion 13. The punch member 22 is adjustably positioned on the member 21 by means of screws 23 and the vertical position of the arm 26 is adjusted by means of screw 37 so that the lower tip, or apex, of the member 22 just engages the planar upper surface 24 of the arm 26 when the portion 16 of the stock is initially engage by the primary punch 11, and the surface 24 of the arm 26 is coplanar with the upper surface of the member 31. The member 51 is adjustably positioned so that the arm and the attached board member 53 engage and support the underface of that portion of that work which extends outwardly from the primary punch 11 and stationary die 13.

As the press brake closes, the ram 10 will move downwardly forming the sheet material portion 16 in the stationary die 13 and the member 22 will pivot the arm 26 and its attached portion 43 about the pivot 27. This action is completed when the punch 11 bottoms in the stationary die portion 13 and the actuator 22 bottoms against the surfaces 41a and 41b, this closed-press position of these components being shown in FIG. 5. As will be evident from a comparison of FIGS. 3 and 5, the pivotal motion of the arm 26 (counterclockwise as viewed in FIG. 5) swings the member 43 carried by the arm under the work and supports the work as it assumes an upwardly inclined position as shown by broken lines at 160 in FIG. 1. The arm, and the member 43 moved by the arm, properly support the work as the forming die cold forms the metal into the bend determined by the tip of the punch 11 and the die cavity 14.

If a thinner gauge sheet material is to be processed through the press brake, a different primary punch and stationary die member will replace the members 11 and 13, the thinner stock requiring a stationary die portion duplicating the die portion 13 but with a cavity having a narrower opening. If the die cavity, comparable to the cavity 14 of FIG. 1, has a narrower opening at the top, in order to maintain the 90 bend between the inclined side surfaces, the depth of the cavity must be considerably shortened and the length of stroke of the primary punch, comparable to the punch 11, must be shortened so that the punch will bottom at a shallower depth against the stock within the cavity when the press is closed.

Since the actuator or auxiliary punch member 22 on the attachment of the present invention will, of course, have its vertical stroke shortened when the vertical stroke of the ram 10 is shortened, the V-shaped groove or cavity, having sidewalls 41a and 41b, in the member 31 must also be, in effect, shortened. This is accomplished, not by interposing a new member 31 with a shallower cavity in it, but by raising the member 31 with relation to the actuator 22 so that even though the actuator has a shorter stroke it yet bottoms against the side surfaces 41a and 41b when the press is closed. This alteration in position of the member 31 is illustrated in FIG. 6. There the shims 360 have been moved to the space between the member 32 and the member 31 which, in effect, raises the surfaces 41a and 41b above their prior position and aligns the apex of the cavity or groove formed by the surfaces 41a and 41b with the elevated apex of the cavity 14 in the replacement stationary die member 13. Since placing the shims 36a in the positions shown in FIG. 6 raises the portion 31, it also raises the pivot 27 carried by the block 28. When the member 31 is raised surface 24 on the arm 26 is raised. The adjusting screws 31 is then utilized to move the block 28 downwardly within its track 29 to lower the arm 26 back to its proper position thereby compensating for the raising of the member 31. The actuator 22 thus, with the press open, engages the surface 26 and with shorter stroke moves into the groove formed by the surfaces 41a and 41b and bottoms against them, the groove having been raised, to compensate for the shortened stroke of the actuator 22,.

As will be evident from FIG. 6 the member 51 will be adjusted downwardly so that the spring loaded abutment 52 is properly positioned and the arm 26 levelled. While the member 31 is shown in one extreme adjusted position in FIG. 3 and in the opposite extreme adjusted position in FIG. 6, it will be understood that by properly interposing one or more of the shims 36a above and below the member 31, any intermediate adjusted position of the member 31 can be obtained. This arrangement permits the attachment to be utilized for a relatively wide range of stock thickness without replacing parts in the attachment.

I claim:

1. An apparatus for lifting and supporting sheet material as it is formed by a bending press of the type in which the moveable ram of the press carries a primary punch element which enters a cavity in a die element supported on the stationary bed of the press with the portion of the sheet material to be formed interposed between the punch and die elements, said apparatus comprising an auxiliary punch secured to the moveable ram of the press, and a work-lifting arm adjacent said auxiliary punch pivotally supported intermediate its ends with the portion on one side of its pivot underlying the sheet material being formed and the portion of said arm on the opposite side of its pivot being engaged by said auxiliary punch simultaneous with the initial engagement of said primary punch element with the interposed portion of the sheet material, continued movement of said auxiliary punch pivoting said arm to lift the sheet material as the portion interposed between said primary punch and die elements is formed by movement of the primary punch element into the die element cavity.

2. An apparatus as claimed in claim 1 in which the position of said arm pivot with relation to the moveable ram of the press is adjustable to coordinate the initiation of the pivotal lifting motion of the arm to various thicknesses of the sheet material interposed between the primary punch and die elements.

3. An apparatus for lifting and supporting sheet material as it is formed by a bending press of the type in which the moveable ram of the press carries a primary punch element which enters a cavity in a primary die element supported on the stationary bed of the press with the portion of the sheet material to be formed interposed between the punch and die elements, said apparatus comprising an auxiliary punch secured to the moveable ram of the press, an auxiliary die secured to the stationary bed of the press and having a portion providing a cavity in which said auxiliary punch bottoms as said primary punch element reaches the limit of its forming stroke, and a work-lifting arm adjacent said auxiliary die pivotally supported intermediate its ends with the portion on one side of its pivot underlying the sheet material being formed and the portion of said arm on the opposite side of its pivot being engaged by said auxiliary punch simultaneous with the initial engagement of said primary punch element with the interposed portion of the sheet material, continued movement of said auxiliary punch into said auxiliary die cavity pivoting said arm to lift the sheet material as the portion interposed between said primary punch and die elements is formed in the primary die element cavity. I 4. An apparatus as claimed in claim 3 in which means are provided for adjusting the position of said arm pivot with relation to the moveable ram of the press to coordinate the initiation of the pivotal lifting motion of the arm to various thicknesses of the sheet material interposed between the primary punch and die elements.

5. An apparatus as claimed in claim 4 in which said arm adjusting means comprises a member slidable along a groove formed in said auxiliary die and an adjusting screw for positioning the member within the groove, said member providing the pivotal axis for said arm.

6. An apparatus as claimed in claim 4 in which the position of said auxiliary die cavity-providing portion is adjustable toward and away from said auxiliary punch to accommodate the differing ram strokes required for forming sheet material of differing thickness.

7. An apparatus as claimed in claim 6 in which a spring-loaded abutment is carried by said auxiliary die and engages the face of said arm opposite that which engages the sheet material, said spring-loaded abutment being positionally adjustable toward and away from said arm for leveling the arm and to accommodate the various adjusted positions of the arm pivot required for various sheet material thicknesses. 

1. An apparatus for lifting and supporting sheet material as it is formed by a bending press of the type in which the moveable ram of the press carries a primary punch element which enters a cavity in a die element supported on the stationary bed of the press with the portion of the sheet material to be formed interposed between the punch and die elements, said apparatus comprising an auxiliary punch secured to the moveable ram of the press, and a work-lifting arm adjacent said auxiliary punch pivotally supported intermediate its ends with the portion on one side of its pivot underlying the sheet material being formed and the portion of said arm on the opposite side of its pivot being engaged by said auxiliary punch simultaneous with the initial engagement of said primary punch element with the interposed portion of the sheet material, continued movement of said auxiliary punch pivoting said arm to lift the sheet material as the portion interposed between said primary punch and die elements is formed by movement of the primary punch element into the die element cavity.
 2. An apparatus as claimed in claim 1 in which the position of said arm pivot with relation to the moveable ram of the press is adjustable to coordinate the initiation of the pivotal lifting motion of the arm to various thicknesses of the sheet material interposed between the primary punch and die elements.
 3. An apparatus for lifting and supporting sheet material as it is formed by a bending press of the type in which the moveable ram of the press carries a primary punch element which enters a cavity in a primary die element supported on the stationary bed of the press with the portion of the sheet material to be formed interposed between the punch and die elements, said apparatus comprising an auxiliary punch secured to the moveable ram of the press, an auxiliary die secured to the stationary bed of the press and having a portion providing a cavity in which said auxiliary punch bottoms as said primary punch element reaches the limit of its forming stroke, and a work-lifting arm adjacent said auxiliary die pivotally supported intermediate its ends with the portion on one side of its pivot underlying the sheet material being formed and the portion of said arm on the opposite side of its pivot being engaged by said auxiliary punch simultaneous with the initial engagement of said primary punch element with the interposed portion of the sheet material, continued movement of said auxiliary punch into said auxiliary die cavity pivoting said arm to lift the sheet material as the portion interposed between said primary punch and die elements is formed in the primary die element cavity.
 4. An apparatus as claimed in claim 3 in which means are provided for adjusting the position of said arm pivot with relation to the moveable ram of the press to coordinate the initiation of the pivotal lifting motion of the arm to various thicknesses of the sheet material interposed between the primary punch and die elements.
 5. An apparatus as claimed in claim 4 in which said arm adjusting means comprises a member slidable along a groove formed in said auxiliary die and an adjusting screw for positioning the member within the groove, said member providing the pivotal axis for said arm.
 6. An apparatus as claimed in claim 4 in which the position of said auxiliary die cavity-providing portion is adjustable toward and away from said auxiliary punch to accommodate the differing ram strokes required for forming sheet material of differing thickness.
 7. An apparatus as claimed in claim 6 in which a spring-loaded abutment is carried by said auxiliary die and engages the face of said arm opposite that which engages the sheet material, said spring-loaded abutment being positionally adjustable toward and away from said arm for leveling the arm and to accommodate the various adjusted positions of the arm pivot required for various sheet material thicknesses. 